I have the “Altered States” DVD from Netflix.
The DVD is a horrible transfer and has, shamefully, never been remastered and resissued.
Despite those flaws with the DVD itself, the film is wonderful.
The story is great, it has talented actors, and the visual effects are amazing (especially for 1980).
I threw the DVD on as a distraction and now and not going to be able to stop the film until it has played through. In some ways it reminds me of “Dreamscape”, but “Dreamscape” is not half as interesting as “Altered States”.
Here are some YouTube clips
Trailer
Scene
Clip
Fan montage